The present invention relates to a sensor and method for measuring changes in environmental conditions. In particular, the present invention relates to a sensor and method using an optical interferometer for an accurate determination of small changes in pressure, temperature or the like.
In the aerospace industry sensors are used to make critical measurements for flight control, engine control and cockpit display systems These sensors include pitot-static probes, air temperature sensors, engine temperature sensors, pressure sensors, angle-of-attack sensors and stall warning sensors. Interferometers have been used in some sensors for measuring the selected parameters. An example of an interferometer is a Fabry-Perot interferometer, which has two partially reflective surfaces that are separated from one another. The environmental condition or parameter to be measured is operably coupled to one or both of the reflective surfaces such that a change in the parameter changes the distance between the surfaces or the optical properties of the media between the surfaces. The interferometer measures the distance between the reflective surfaces based on interference between light reflecting from the surfaces. A variety of different interferometric sensors make use of this principle.